Color television device



sept. 6, C, W, GEER 2,480,848

COLOR TELEVISION DEVICE Filed July 11, 1944 INM/#Toe 3,/ @mais W/L/.APD 655@ ibn. w

F0 THFF/-EM Patented Sept. 6, 1949 UNITED STATES PATENT OFFICE 40 Claims. 1

This invention relates to apparatus for use in television reception, and concerns especially the production of color effects by a television receiver. A principal object of the invention is to make possible the practical production of color images by television receiving apparatus.

Another important object is to employ transmitted signals which correspond with different colors, for example the respective primary colors, of the original subject in such a manner that the respective signals individually activate colorproducing materials in close simulation of the original colors of the subject.

A further object of the invention is to produce television receiving apparatus which will yield substantially full color images through the employment of a plurality of separate electron guns, each controlled by a respective signal originating in transmitting apparatus and corresponding with a color to be produced in the receiver, for example a primary color.

A further object of the invention is to provide a screen adapted for use in a receiver and provided with a plurality of different elements, each of which is adapted and arranged for operation thereupon by corresponding rays, such as the usual cathode rays.

A further object is to provide a plurality of elevatlons upon a receiving screen so arranged that rays from different electron guns may be made to impinge selectively upon surfaces corresponding with the respective rays from the electron guns, the respective rays in turn corresponding with colorsof the subject. A further object is to provide a receiving screen having various surfaces facing in different directions and adapted for selective impingement thereupon of rays representing different colors. Such differently directed surfaces may be placed upon one side of the screen, or both sides of a transparent sheet may carry certain of the surfaces. According to a particular embodiment, the respective surfaces are coated with different materials commonly referred to as fluorescent materials, but more properly known as phosphors These phosphors are selectively subjected to electron bombardment from cathodes of the electron guns to produce the phenomenon of 'cathodolurninescence. By means of dierent phosphors, different lumlnescences are obtained corresponding with the primary or other colors selected.

A further object is to employ the various luminescent materials upon a screen in a modified iconoscopeV or klnescope, the screen being translucent, whereby the primary colors produced by the phosphors blend properly to yield color images closely simulating the colors of the subject. By employment with a projection lens,

a colored image so formed may be projected upon a viewing screen.

Another object of the invention is to provide a screen wherein all of the surfaces for all the phosphors are disposed upon a single face of the screen, and it is also an object to employ such a screen in combination with at least three electron guns so that all of the guns cause their electrons to impinge upon the respective surfaces of the one face of the screen. Another object is to cause the back wall of an iconoscope type of bulb to serve as the screen, the phosphor-carrying surfaces being disposed upon the inner face of the back wall.

A further object is to avoid the use of rotating mechanical lters.

Other features and objects of the invention will become apparent to those skilled in the art from the accompanying drawing wherein certain embodiments are disclosed for illustrative purposes only. l

In the drawing,

Fig. 1 is a longitudinal vertical section through a bulb of the kinescope type to which the present invention is applied;

Fig. 1a indicates an alternate use to which the invention may be put:

Fig. 2 is a cross section taken on the line 2 2 of Fig. 1;

Fig 3 is a cross-sectional detail of the screen structure of Figs. 1 and 2;

Fig. 4 is chiefly a plan view, a portion being broken away, showing a modification:

Fig. 5 is an end view of the form of Fig. 4;

Fig. 6 is a fragmentary view in plan of a modified form of screen arrangement;

Fig. '7 is a cross section taken on the line 1-1 of Fig. 6;

Fig. 8 is a fragmentary cross section of a modied form of the screen construction of Fig. 3; and

Fig. 9 is a fragmentary sectional detail of a further modified form of screen construction.

One embodiment of the invention may, as dllustrated in Figs. 1 and 2, comprise an evacuated glass bulb I0 in which a screen i2 of the present invention is disposed in viewing position and in proper position for impingement thereupon of cathode ray beams from a plurality of electron guns Il, It and i6 mounted in a plurality of suitably directed gun necks il preferably integrally formed with the bulb I.. The arrangement of 3 the necks I8 is such as to direct the beams from the respective guns I4. I5 and I6 at varying angles in order to produce impingement upon the screen I2 from different directions.

The bulb I may be constructed similarly to the y construction of an iconoscope or kinescope, and is provided with a rear wall 20 through which an image formed upon the screen I2 may be viewed, or, as illustrated in Fig. 1a, through which the image on the screen I2 may be projected through an appropriately carried lens 22 upon a projection screen 24.

The number of gun necks I8 and guns carried thereby will conform with the number of principal colors that are to be produced upon the screen I2. For some purposes it may be sufli.- cient to produce two colors, in which case only two gun necks I8 will be provided for the guns I4 and I5 for the impingement of cathode rays upon the forward face of the screen I2. If a third color is to be produced, this will be accomplished through the medium of the gun I6 which directs electrons upon the back wall of the screen I2. In order that the back wall 20 of the bulb I0 may be free for viewing or projection purposes, the gun neck I8 for the third gun I6 is necessarily disposed at an angle out of line with the screen I2. Thus, the gun neck I8 for the gun I6 will be set adjacent one pointof juncture ofthe back wall 20 of the bulb I0 with the generally circular side wall 25 of the bulb. The arrangement of the g-uns I4, I and I6 for three color work, as indicated in Figs. 1 and 2, is employed where the screen construction I2 requires the use of the back wall of the screen as well as the front wall. However, where appropriate construction of the screen I2 permits, the third gun may be disposed, in an alternative embodiment, for projection upon the front wall of the screen, as illustrated in Figs. 4 and 5 and for this purpose the third gun neck I8 is disposed forward of the screen I2 in properly spaced arrangement so that the corresponding third gun I6a cooperates with the guns I4 and I5 to direct electrons toward the front face of the screen I2 at equidistantly spaced angles.

The screen I2, in the preferred embodiment shown in Figs. 1, 2, and 3, comprises' a sheet 30 of transparent material, typically glass, the rear face 32 of which may be smooth for impingement thereupon of electrons from the gun I6. The forward face is provided with a plurality of closely ruled ridges 33 of triangular cross section, each of which ridges provides a face 34 for impingement thereupon of electrons from the gun I4, and an opposite face 35 for impingement thereupon of electrons from the gun I5. The angle 36 between the faces 34 and 35 is such with respect to the angle between the axes of the electron guns I4 and I5 as to avoid any overlap of the beam from the gun I4 upon the faces 35, and likewise to avoid any overlap of the beam from the gun I5 upon the faces 34.

Where a three color image is to be produced employing the three guns I4, I5 and I6, the faces 32, 34 and 35 are respectively coated with suitable phosphors adapted upon activation by the respective beams from the respective guns I4, I5 and I3 to yield the desired colors. For example, the principal colors to be produced may be red, blue, and green, green being a preferable color to the primary color yellow in order to overcome atness. In any event, the three colors chosen are those which appear approximately equi-distantly spaced on the well known color wheel representing the spectrum. For the present purpose, the rear face 32 may be coated,

for example, with a phosphor 32a capable of yielding a green color upon activation, such a material being, for example, zinc orthosilicate. Similarly, the angularly disposed faces 34 of the ridges 33 may be coated with a material 34a capable of yielding a blue color upon activation, for which purpose calcium tungstate, for example, may be used, and the faces 35 may be coated with a material 35a capable of yielding a. red color upon activation, such as, for example, calcite or zinc beryllium silicate. Thus, when a color signal of corresponding frequency is supplied to the gun I6, the electron bombardment upon the material 32a applied to the rear face 32 will produce green, and, similarly, color signals of proper frequencies supplied to the guns I4 and I5 will produce corresponding electronic bombardments upon the two sets of faces 34 and 35 to produce blue and red colors, respectively. The resultant color blend seen through the rear Wall 20 of the bulb I0 will yield an image simulating the natural colors of the subject scanned by a transmitting device from which the appropriate color signals are initially received. Such transmitting devices are well known in the art.

Should it be desirable to analyze the composite color signal produced by the transmitting apparatus, appropriate known or preferred devices may be employed to supply the respective guns I4, I5 and I6 with individual signals of proper frequencies, such devices forming no portion of the present invention but being known in the art. Similarly, where the beam projected by the gun I6 is applied to the rear face, suitable means for reversing the effect of the beam upon the screen I2 will be employed, this specific means likewise not being a portion of the present invention.

Since the sheet 30 constituting the body member of the screen I2 is transparent, and since the coatings of lphosphors applied respectively to the rear face 32 and the angular faces 34 and 35 of the ridges 33 are activated to yield the desired respective colors, the screen I2 as a Whole will function as a translucent unit rather than asa transparent unit. Where rulings or groovings are employed in the production of the ridges 33 and the corresponding series of faces 34 and 35, the spacing of the rulings or groovings will preferably be less than the resolving power of the normal eye, and for example may be in the order of ridges per inch.

Since the laxes of the three guns I4, I5 and I6 are disposed at angles other than perpendicular to the screen I2, there would be a keystoning effect upon their beams if not avoided. However, the keystoning tendency may be corrected by any known or preferred circuit or other means, not a part of the present invention.

Where it is permissible to employ only two principal colors, the gun I6 may be omitted, and the guns I4 and I5 operated at appropriate frequencies for activation of suitable phosphors. Here, the two colors selected will be spaced about apart on the color wheel spectrum.

In order to obtain three-color effects, and to eliminate reversing of the beam projected on the rear face 32 of the screen I2 from the electron gun I6, the gun I6 may be shifted to the forward side of the screen I2, as indicated by the gun IBa of Figs. 4 and 5, the three guns I4, I5 and IBa being equi-distantly arranged, as above described. Here, the back wall of the screen I2 will not .be

employed for the impingement of electrons and for reception of a corresponding phosphor. Instead, a. modified front face will be employed on the screen I2, preferably as indicated' in Figs. 6 and 7, where, trihedrons 40 are employed on the front face. The result is the formation of three faces 4I, 42 and 43 on each trihedron 43, the respective faces of the various trihedrons presenting a corresponding series of faces to the respective electron guns I4, I5 and I 5a. These series of faces 4I, 42 and 43 receive corresponding phosphors, as in the case of the various faces 32, 34 and 35 of the screen I2 of Fig. 3, and the resultant color effects will correspond with those produced by the screen of Fig; 3 and may be viewed from the back wall of the screen in thev same manner. Such a construction of the screen also adapts it to placement directly upon the rear Wall 20 of the bulb I0, or to employment as the rear wall 20, as indicated in Fig. 4. This screen construction preferably includes extension of the respective faces 4|, 42 and 43 to form trihedral depressions 44 in the body of the screen I2, whose walls thus respectively receive the same electron bombardments as the corresponding faces 4I, 42, and 43. In this construction the trihedrons 40 and trihedral depressions 44 are alternately disposed.

The type of screen construction of Figs. 6 and '7 may be adapted for use either with black and white or with color by employing it in the position of the screen I2 of Fig, 1 and using the reverse -face 45 v(Fig. 7) in the same manner that the reverse face 32 of the screen of Figs. 1, 2 and 3 is employed. 'For example, either the reverse face 45 or one of the trihedral faces 4I, 42 and 43 may be employed for black and white and the other prepared for color use, in which case a fourth neck I8 provided with a suitable electron gun would be employed. Of course, somewhat similar effects could be obtained by employing tetrahedrons in order to provide a fourth face, especially if overlapping of rays from the various guns in color work would not be objectionable.

Other possible arrangements of surfaces for impingement of respective electrons are shown in Figs. 8 and 9. The form of screen shown in Fig. 8 is a. slightly modif-led form of the screen I2 of Fig. 3, the difference being that the ridges 33 are spaced somewhat to provide flat valleys 45 between the ridges. With this form of construction the width of the valleys is such, with respect to the height of the ridges 33 and the angles of the beams falling upon the two sets of surfaces 34 and 35, that there will be no overlapping of rays in the valleys. rIlhus, as indicated in Fig. 8, rays from one electron gun will be cut off by the tops of the ridges so that those rays from the respective gun which reach the corresponding valley 46 will strike the valley beyond the median line thereof and beyond the point at which rays from the opposite electron gun reach the valley.

As shown in Fig. 9, semi-spherical beads 48 may be employed, or the indicated semi-circular constructions may represent ridges with semicylindrical tops. With this construction, the impingement of electrons at sufficiently flat angles, as indicated by the various arrows, will result in only an insignificant amount of overlap, especially for two-color reproduction, and, therefore, only a very slight color confusion at the points or lines of juncture. Other configurations may be employed, such as cones and irregularly shaped bodies, sandpaper being a possible example of the latter.

In constructing the apparatus, substantially the same procedure will be employed as is used in building iconoscopes and kinescopes, and especially that employed in the construction of iconoscopes with signal multipliers. The electron guns I4, I5, I6 and I5a are indicated as being of a well understood construction, the exposed terminal portions 5II of the guns being sealed into the gun necks I3 in standard fashion and carrying leads 52 as required. The guns are shown as comprising the usual cathodes, anodes and other portions of a lens system 53, as seen in Fig, 1, and, in conjunction therewith, magnetic deflection yokes 54 are disposed about the gun necks I8 although, as well understood in the art, static deflection plates may be substituted therefor.

The operation of apparatus of the present invention has been described in general in the above outline. Briefly, the operation comprises the impingement upon the screen I2 of electrons from the various electron guns I4, I5, I5 and Ilia. With the construction and arrangement of Figs. 1, 2 and 3 electrons are projected from the guns I4 and I5 upon the forward face of the screen I2 at angles with respect to each other and with respect to the angularly disposed faces 34 and 35 such that the bombardment of electrons from the gun I4 falls only upon the corresponding angularly disposed surfaces 34, whereby only the phosphor 34a is activated by the corresponding rays. Similarly, the electron bombardment from the electron gun I5 falls only upon the phosphor layer 35a on the faces 35. The axes of the guns I4 and I5 are so related with respect to the angle 35 between the faces 34 and 35 that the only impingement of electrons is upon the respective faces, there being, for example, no impingement of electrons from the gun I5 upon the faces 34, nor any impingement of electrons in the gun I4 upon the faces 35. As a result, the phosphor layers 34a and 35a. are respectively activated according to the intensity of the respective electron impingement. Since the colorings of the activated phosphors correspond respectively with the original colors of the subject under whose influence the corresponding color signals were generated, those original colors are simulated or reproduced upon the faces 34 and 35 of the screen I2. Similarly, a corresponding third color is produced by the gun I6 upon the phosphor layer 32a on the rear face 32 of the screen I2. By reason of the coatings or layers 32a, 34a and 35a upon the transparent glass body 30, the screen as a whole becomes translucent under the influence of the projected rays from the electron guns and yields a composite image viewable through the back wall 20, or projectible through the optical lens 22 upon the projection screen 24.

The same general effect is obtained with the construction of Figs. 4, 5 and 6, where the three electron guns I4, I5 and IBa are arranged to project their rays upon the forward face of the screen I2 and three corresponding phosphors are respectively applied to respective series of the faces 4I, 42 and 43 of the trihedrons 40, the inner face of the back wall 20 providing these phosphor-bearing surfaces, and said back wall 20 constituting the screen I2. These forms of Figs. l to 6, inclusive, provide for three-color reproduction. Two-color reproduction may be effected by employing the ruling or grooving of Figs. 2, 3 and '7 with only two electron guns, such as the guns I4 and I5 of Figs. l and 4. Similar two-color effects may be produced by means of either semi-spherical or semi-cylindrical lining. as indicated by Fig. 8.

With the means of this invention rotating mechanical filters may be avoided.

As previously indicated, correction to avoid keystoning, and analysis of composite signals transmitted by sending apparatus when desired to provide respective color signals of proper frequency for the individual electron guns, may be effected by any suitable means, the details of which constitute no part of the present invention.

It is to be understood that the specific embodiments herein described are disclosed merely for the purpose of illustrating the generic invention represented, since it will be apparent that many variations may be made by those skilled in the art. It is intended therefore to cover all such modifications as fall within the scope of the appended claims.

I claim as my invention:

1. A television screen comprising: a translucent sheet provided on one side with a plurality of series of faces, the respective series being faced in different directions and adapted for impingement thereupon of electrons from different sources.

2. A television screen comprising: a translucent sheet; projections carried by said sheet and providing one series of faces facing in one direction for impingement thereupon of electrons from one source; and a second series of faces facing in another direction for impingement thereupon of electrons from another source, said faces being arranged for selectively receiving electrons only from the respective sources; and different materials carried by the respective series of faces and adapted to be separately activated by the electrons from the respective sources.

3. A television screen comprising: a sheet of material provided with a plurality of series of projecting faces, the respective series faced in different directions and adapted for impingement thereon respectively of electrons from dif- 4 ferent directions; and different phosphors disposed upon the respective series of projecting faces and adapted to be activated by the respective electrons to yield different color effects. the spacing of said projections being less than the resolving power of the normal eye.

4. In television apparatus: a screen provided with a plurality of series of surfaces, the various series having their surfaces disposed at different angles for impingement respectively thereon f electrons from corresponding electron guns; and a corresponding plurality of cathodoluminescent phosphors respectively disposed upon said series of surfaces and adapted to yield corresponding principal colors upon cathode activation.

5. In television apparatusin combination: a bulb; a screen disposed within said bulb; a plurality of electron guns carried by said bulb and having their axes directed toward said screen at different angles, said guns being adapted to produce different electron bombardments respectively under influence of correspondingly differentI frequencies; and a plurality of series of faces provided upon said screen and disposed at different angles for selective impingement of electrons thereupon from the respective guns.

6. A combination according to claim 5 wherein the different series of faces respectively carry 8 upon activation by electron bombardment from the respective guns.

7. A combination according to claim 5 wherein the angles of the different series of faces are respectively arranged with respect to correspondlng guns to avoid overlap of bombardment from one gun upon faces of a respectively different series.

8. A combination according to claim 5 wherein said plurality of series of faces project from said screen at respectively different angles, the respective series carrying respectively different phosphors capable of being activated by the respective guns to yield a corresponding number of different principal colors.

9. In combination in television apparatus: a bulb; a screen disposed in said bulb and composed of transparent material; a plurality of series of faces carried by said screen and projecting from said screen at respectively different angles; a plurality of electron guns carriedby said bulb and positioned to direct electrons respectively upon said plurality of series of faces; and a plurality of different phosphors disposed respectively upon said series of faces and adapted to be activated by the respective guns to produce different eiects upon said faces.

10. A combination according to claim 9 wherein said faces are disposed upon opposite sides of said screen.

11. A combination according to claim 9 wherein said phosphors yield different colors upon activation by said guns.

12. A television screen including: a translucent sheet provided on one side with three series, of faces, the respective series being faced in different directions for impingement thereupon of electrons from different sources.

13. A television screen including: a translucent sheet provided on one side with three series of faces, the respective series being faced in dierent directions for impingement thereupon of electrons from different sources, each of said faces being at an angle of approximately 5 ninety degrees from the faces in the other series thereof.

14. A television screen including: a, translucent sheet provided on one side with three series of faces, the respective series being faced in different directions` for impingement thereupon of electrons from different sources, each of said faces being flat and disposed at an angle of approximately ninety degrees from the faces in the other series thereof.

15. A television screen including: a translucent sheet provided on one side with a plurality of projecting trihedrons, each of the faces of which is adapted for impingement thereon of electrons from different sources.

16. A television screen including: a translucent sheet provided on one side with three series of faces, the respective series being faced in different directions for impingement thereupon of electrons from different sources, each of said faces carrying an electron-responsive material.

17. A television screen including: a translucent sheet provided on one side with a plurality of projecting trihedrons, each of the faces of which is adapted for impingement thereon cf electrons from a different source, each of said faces carrying an electron-responsive material.

18. A television screen including: a translucent sheet provided on one side with a plurality of ridges, each ridge forming a pair of faces phosphors adapted to yield different colorings directed in different directions, and each of said faces carrying an electron-responsive material.

19. A television screen including: a translucent sheet provided on one side with a plurality of ridges, each ridge forming a pair of faces directed in different directions, and each of said faces carrying an electron-responsive material, said ridges being parallel and spaced apart.

20. In a television apparatus, the combination of: a bulb; a screen associated with said bulb and having one side thereof within said bulb, said side having a plurality of series of faces provided thereon and disposed at different angles for selective impingement of electrons thereupon from different directions, iat least some of said faces carrying electron-responsive materials; and a plurality of electron guns carried by said bulb, each of which has its axispfdirected toward said screen in one of said directions, each of said guns being adapted to produce an electron bombardment upon one of said series of faces.

21. In a television apparatus, the combination of a bulb; a. screen associated with said bulb and having one side thereof within said bulb, said side having three series of faces provided thereon and disposed at different angles for selective impingement of electrons thereupon from different directions, at least some of said faces carrying electron-responsive materials; and three electron guns carried by said bulb, each of which has its axis directed toward said screen in one of said directions, each of said guns being adapted to produce an electron bombardment upon one of said series of faces.

22. In a television apparatus, the combination of: a bulb; a screen associated with said bulb and having one side thereof within said bulb, said side having a. plurality of series of faces provided thereon and disposed at different angles for selective impingement of electrons thereupon from different directions, at least some of said faces carrying electron-responsive materials; and a plurality of electron guns carried by said bulb onvthe same side of said screen, each of which has its axis directed toward said screen in one of said directions, each of said guns being adapted to produce an electron bombardment upon one of said series of faces.

23. In a television apparatus, the combination of a bulb; a screen associated with said bulb and having one side thereof within said bulb, said side having three series of faces provided thereon and disposed at different angles for selective impingement of electrons thereupon from different directions, at least some of said faces carrying electron-responsive materials; and three electron guns carried by said bulb on the same side of said screen, each of which has its axis directed toward said screen in one of said directions, each of said guns being adapted to produce an electron bombardment upon one of said series of faces.

24. In a television apparatus, the combination of: a bulb; a screen associated with said bulb and having one side thereof within said blb,`

l0 25. A television screen including: a translucent sheet provided on one side with a plurality o series of faces, the respective faces being fac in different directions and adapted for implnsement thereupon oi.' electrons from different sources, each of said series of faces carrying a phosphor adapted to be activated by electrons from one of said sources to yield a given color.

26. A television screen including: a translucent sheet provided on one side with a plurality oi' series 0f faces, the respective faces being faced in different directions and adapted for impingement thereupon of electrons from different Sources, each of said series of faces carrying a phosphor adapted to be activated by electrons from one of said sources to yield a different color.

27. A television screen including: a translucent sheet provided on one side with three 'series of faces, the respective faces of each series thereof being faced in different directions and adapted for impingement thereupon of electrons from different sources, each of said series carrying a cathodoluminescent material adapted to be activated by electrons from one of said sources, so as to yield a three-color image.

28. Electronic apparatus of the class described comprising a support surface element, a multiplicity of coated and color responsive pyramidal impact elements each having a plurality of surface areas 0f a sub-elemental size, each of said pyramids having its base secured to said support surface element and its apex lying above the support, said surface coatings of the impact surface areas of the pyramids being formed of a plurality of materials adapted to effect a, response under electron impact which closely approximates predetermined colors of a multicolor additive color system, the said groupings of the coatings upon sub-elemental area size surface elements of the pyramids being such that each pyramidal surface has a coating of one of the color response materials and collectively the plurality of surface areas when projected upon the support base substantially correspond in size to an elemental area of finite size, and means for developing a plurality of modulatable electron beams each adapted to be directed toward the said supported pyramidal elements from directions acutely inclined to the central pyramid axis so that the said beams individually scan the subelementai area size coated surface areas of the pyramids and collectively produce signal responses representative of a plurality of colors.

29. Electronic apparatus of the class described comprising a support surface element, a multiplicity of coated and color responsive impact elements eachof a sub-elemental area size and each secured to said support surface element, said coatings of the impact elements of the subelemental area size being of a plurality of materials adapted to eect a response under electron impact which closely approximates predetermined colors of a multicolor additive color system, the said groupings of the sub-elemental area size elements being such that substantially at least one coated element of each color response is included within an area corresponding to an elemental area of finite size, and means for developing a plurality of modulatable electron beams each adapted to be directed toward the said support surface element to scan individually the sub-elemental area size coated elements of a single color response only.

30. An electron tube for use in a color television system comprising a target element forming a quasi-focal plane which is adapted to be impacted by electron beams substantially focused thereat, a group oi' substantially elementary size tetrahedral surfaces systematically located relative to the quasi-focal plane of the tube with each related surface area of each of the groups of tetrahedral elements being color responsive in one only of a series of component colors as used in additive color processes, and electron gun means for developing a plurality of electron scanning beams and for directing the resultant electron beams toward the target areas in a man.. ner for restricting the scanning of the tetrahedral target faces by the separate electron scanning .beams each to one only of the group of color responsive areas of the tetrahedral surfaces.

31. A color television system comprising a n electron tube having a target based upon a, quasifocal plane adapted to be impacted by an electron beam substantially focused thereat, a multiplicity of substantially elementary size pyramidal elements having a plurality of surfaces systematically located relative to the quasi-focal plane of the tube with corresponding faces of each of the multiplicity of pyramidal elements being light emissive, as a group under electron impact, to radiate light, when activated, in one of a pluraiity of selected component colors for producing additive color images, and a plurality of electron guns for developing a plurality of individual electron scanning beams adapted to be directed toward the target areas so that individual electron beams are as restricted in the scanning pattern as to impact one only of the several color responsive surfaces of the pyramids.

32. A color television system comprising an electron tube having a target based upon a quasifocal plane adapted to be impacted by an electron beam substantially focused thereat, a multiplicity of substantially elementary size tetrahedral elements having a plurality of surfaces systematically located relative to the quasi-focal plane of the tube with each similar surface of the multiplicity of velements being light emissive as a group to radiate light, when activated, in one of a plurality of selected component colors for producing additive color images and a plurality of means for developing individual electron scanning beams adapted to be directed toward the target areas so that the individual scanning beams are each adapted to scan one group only of the group of multiplicities of the elementary surfaces.

33. A color television system comprising an electron tube having a target based upon a quasifocal plane adapted to be impacted by an electron beam substantially focused thereat, a group of substantially elemental size tetrahedral elements systematically located in predetermined relationship relative to the quasi-focal plane of the tube with each corresponding face of the tetrahedral elements being color discriminative as a group, when activated, to be operative only in relationship to one of the plurality of selected component colors of an additive color process, means for developing a plurality of electron scanning beams and for directing each separate electron beam upon like color responsive elements only, means for scanning the surfaces of the tetrahedra by the separately produced electron scanning beams, and means for restricting the scanning by eachof the separate electron scanning beams to one. only of the group of multiplicities of the elemental size color responsive elements.

34. A color television tube comprising a target electrode based upon a quasi-focal plane adapted to be impacted by an electron beam substantially focused thereat, a group of multiplicities of substantially elementary size tetrahedral elements systematically located relative to the quasi-focal plane of the tube with the faces of the multiplicities of tetrahedral elements being light emissive in different colors so that, as a group, the elements are adapted to radiate light, when activated, in the several selected component colors for producing additive color images, means for developing a plurality of electron scanning beams and for directing the resultant electron beams upon the target area, and means for scanning like faces of each tetrahedral element carried upon the target areas by the separately produced electron scanning beams so that collectively the electron beam activation of the light emissive tetrahedral faces develops an additive tricolor image.

35. Electronic tube apparatus for use in a color television system comprising an envelope having included therein a multiplicity of pyramidal elements and a target area for supporting said elements with the target surface forming a quasifocal plane adapted to be impacted by an electron beam focused substantially thereat, a coating of luminescent materials on each of three of the faces of the pyramidal elements with each face being adapted to luminesce with electron beam excitation to radiate light in a different one of a plurality of selected component colors for producing additive color` images, means for developing a plurality of electron scanning beams equal in number to the selected component colors and for directing the resultant electron beams -upon the pyramidal faces to produce light, means for scanning the pyramidal elements supported on the target by the separately produced electron scanning beams, means for restricting the scanning of like color responsive pyramidal faces by the separate electron scanning beams each to one only of the plurality of electron beams whereby collectively a color image is developed on the target.

36. Electronic apparatus of the class described comprising a support surface element, a multiplicity of impact elements each having a luminescent coating and each of a sub-'elemental area size and each secured to said support surface element, said luminescent coatings of the impact elements of the sub-elemental size areas being of a plurality of materials adapted to eifect a response under electron impact which closely approximates predetermined colors of a multicolor kadditive color system, the said groupings of the sub-elemental size area elements being such that substantially at least one coated element of each color response is included within an area corresponding to an elemental area of iinite size, and means for developing a plurality of modulatable electron beams each adapted to be directed toward the said support surface element to scan individually the sub-elemental size coated elements of a single color response only.

37. A color television system comprising an electron tube having a target based upon a quasifocal plane adapted to be impacted by an electron beam substantially focused thereat, a group of multiplicities of elements systematically located in predetermined relationship relative to the quasi-focal plane of the tube with each of the multiplicities of elements being color discriminative as a group, when activated, to be operative 13 only in relationship to one of the plurality of selected component colors of an additive color process, means for developing a plurality of electron scanning beams and for directing the resultant electron beams upon the elements, means for scanning the elements by the separately produced electron scanning beams, and means for restricting the scanning by each of the separate electron scanning beams to one only of the group of multiplicities of the elemental size elements.

38. Electronic apparatus of the class described comprising a support surface element, a multiplicity of coated and color responsive pyramidal impact elements each having a plurality of surface areas of a sub-elemental size, each of said pyramids having its base secured to said support surface element and its apex lying above the support, said surface coatings of the impact surface areas of the pyramids being formed of a plurality of materials adapted to eiect a response under electron impact which closely approximates predetermined colors of a multicolor additive color system, the said groupings of the coatings upon sub-elemental area size surface elements of the pyramids being such that each pyramidal surface has a. coating of one of the color response materials and collectively the plurality of surface areas when projected upon the support base substantially corresponding in size to an elemental area of finite size, and means for developing a plurality of modulatable electron beams each adapted to be directed toward the said supported pyramidal elements from directions acutely inclined to the central pyramid axis so that the said beams individually scan the subelemental area size coated surface areas of the pyramids and collectively produce signal responses representative of a plurality of colors.

39. A color television system comprising an electron tube having a target based upon a quasifocal plane adapted to be impacted by an electron beam substantially focused thereat, a group of multiplicities of substantially elementary size surfaces systematically located relative to the quasi-focal plane of the tube with each of the 4 multiplicities of elements being light emissive as a group to radiate light, when activated, in one of a plurality of selected component colors for producing additive color images, means for developing a plurality of electron scanning beams and/for directing the resultant electron beams upon the target areas, means for scanning the target areas by the separately produced electron scanning beams, and means for restricting the scanning of the target by the separate electron scanning beams each to one only of the group of multiplicities of the elementary surfaces.

40. In a system of additive color television, an electron beam receiving target responsive chromatically in predetermined component colors collectively producing substantially white light with the response being controlled in accordance with the direction and intensity of electron beam impact thereon and means for developing a plurality of electron beams each angularly disposed relative to the target and to each other and each adapted to be controlled by signal energy representative of one component color so that the target is impacted from different angles by signal controlled electron beamsrepresentative of each component color of the additive system.

CHARLES WILLARD GEER..

REFERENCS CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,934,821 Rudenberg Nov. 14, 1933 1,988,605 Michelssen Jan. 22, 1935 2,074,737 Wolff Mar. 23, 1937 2,083,203 Schlesinger June 8, 1937 2,179,205 Toulon Nov. 7, 1939 2,307,188 Bedford .L Jan. 5, 1943 2,310,863 Leverenz Feb. 9, 1943 2,330,172 Rosenthal Sept. 21, 1943 FOREIGN PATENTS Number Country Date 328,606 Italy Dec. 13, 1933 395,578 Great Britain July 20, 1933 562,168 Great Britain June 2l, 1944 

